
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>Operating System Utilities &#8212; Python 3.6.3 documentation</title>
    <link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" />
    <link rel="stylesheet" href="../_static/pygments.css" type="text/css" />
    <script type="text/javascript">
      var DOCUMENTATION_OPTIONS = {
        URL_ROOT:    '../',
        VERSION:     '3.6.3',
        COLLAPSE_INDEX: false,
        FILE_SUFFIX: '.html',
        HAS_SOURCE:  true,
        SOURCELINK_SUFFIX: '.txt'
      };
    </script>
    <script type="text/javascript" src="../_static/jquery.js"></script>
    <script type="text/javascript" src="../_static/underscore.js"></script>
    <script type="text/javascript" src="../_static/doctools.js"></script>
    <script type="text/javascript" src="../_static/sidebar.js"></script>
    <link rel="search" type="application/opensearchdescription+xml"
          title="Search within Python 3.6.3 documentation"
          href="../_static/opensearch.xml"/>
    <link rel="author" title="About these documents" href="../about.html" />
    <link rel="index" title="Index" href="../genindex.html" />
    <link rel="search" title="Search" href="../search.html" />
    <link rel="copyright" title="Copyright" href="../copyright.html" />
    <link rel="next" title="Importing Modules" href="import.html" />
    <link rel="prev" title="Utilities" href="utilities.html" />
    <link rel="shortcut icon" type="image/png" href="../_static/py.png" />
    <link rel="canonical" href="https://docs.python.org/3/c-api/sys.html" />
    
    <script type="text/javascript" src="../_static/copybutton.js"></script>
    <script type="text/javascript" src="../_static/switchers.js"></script>
    
    
 

  </head>
  <body>  
    <div class="related" role="navigation" aria-label="related navigation">
      <h3>Navigation</h3>
      <ul>
        <li class="right" style="margin-right: 10px">
          <a href="../genindex.html" title="General Index"
             accesskey="I">index</a></li>
        <li class="right" >
          <a href="../py-modindex.html" title="Python Module Index"
             >modules</a> |</li>
        <li class="right" >
          <a href="import.html" title="Importing Modules"
             accesskey="N">next</a> |</li>
        <li class="right" >
          <a href="utilities.html" title="Utilities"
             accesskey="P">previous</a> |</li>
        <li><img src="../_static/py.png" alt=""
                 style="vertical-align: middle; margin-top: -1px"/></li>
        <li><a href="https://www.python.org/">Python</a> &#187;</li>
        <li>
          <span class="language_switcher_placeholder">en</span>
          <span class="version_switcher_placeholder">3.6.3</span>
          <a href="../index.html">Documentation </a> &#187;
        </li>

          <li class="nav-item nav-item-1"><a href="index.html" >Python/C API Reference Manual</a> &#187;</li>
          <li class="nav-item nav-item-2"><a href="utilities.html" accesskey="U">Utilities</a> &#187;</li>
    <li class="right">
        

    <div class="inline-search" style="display: none" role="search">
        <form class="inline-search" action="../search.html" method="get">
          <input placeholder="Quick search" type="text" name="q" />
          <input type="submit" value="Go" />
          <input type="hidden" name="check_keywords" value="yes" />
          <input type="hidden" name="area" value="default" />
        </form>
    </div>
    <script type="text/javascript">$('.inline-search').show(0);</script>
         |
    </li>

      </ul>
    </div>    

    <div class="document">
      <div class="documentwrapper">
        <div class="bodywrapper">
          <div class="body" role="main">
            
  <div class="section" id="operating-system-utilities">
<span id="os"></span><h1>Operating System Utilities<a class="headerlink" href="#operating-system-utilities" title="Permalink to this headline">¶</a></h1>
<dl class="function">
<dt id="c.PyOS_FSPath">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <code class="descname">PyOS_FSPath</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*path</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyOS_FSPath" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><p>Return the file system representation for <em>path</em>. If the object is a
<a class="reference internal" href="../library/stdtypes.html#str" title="str"><code class="xref py py-class docutils literal"><span class="pre">str</span></code></a> or <a class="reference internal" href="../library/stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal"><span class="pre">bytes</span></code></a> object, then its reference count is
incremented. If the object implements the <a class="reference internal" href="../library/os.html#os.PathLike" title="os.PathLike"><code class="xref py py-class docutils literal"><span class="pre">os.PathLike</span></code></a> interface,
then <a class="reference internal" href="../library/os.html#os.PathLike.__fspath__" title="os.PathLike.__fspath__"><code class="xref py py-meth docutils literal"><span class="pre">__fspath__()</span></code></a> is returned as long as it is a
<a class="reference internal" href="../library/stdtypes.html#str" title="str"><code class="xref py py-class docutils literal"><span class="pre">str</span></code></a> or <a class="reference internal" href="../library/stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal"><span class="pre">bytes</span></code></a> object. Otherwise <a class="reference internal" href="../library/exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal"><span class="pre">TypeError</span></code></a> is raised
and <code class="docutils literal"><span class="pre">NULL</span></code> is returned.</p>
<div class="versionadded">
<p><span class="versionmodified">New in version 3.6.</span></p>
</div>
</dd></dl>

<dl class="function">
<dt id="c.Py_FdIsInteractive">
int <code class="descname">Py_FdIsInteractive</code><span class="sig-paren">(</span>FILE<em>&nbsp;*fp</em>, const char<em>&nbsp;*filename</em><span class="sig-paren">)</span><a class="headerlink" href="#c.Py_FdIsInteractive" title="Permalink to this definition">¶</a></dt>
<dd><p>Return true (nonzero) if the standard I/O file <em>fp</em> with name <em>filename</em> is
deemed interactive.  This is the case for files for which <code class="docutils literal"><span class="pre">isatty(fileno(fp))</span></code>
is true.  If the global flag <code class="xref c c-data docutils literal"><span class="pre">Py_InteractiveFlag</span></code> is true, this function
also returns true if the <em>filename</em> pointer is <em>NULL</em> or if the name is equal to
one of the strings <code class="docutils literal"><span class="pre">'&lt;stdin&gt;'</span></code> or <code class="docutils literal"><span class="pre">'???'</span></code>.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyOS_AfterFork">
void <code class="descname">PyOS_AfterFork</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyOS_AfterFork" title="Permalink to this definition">¶</a></dt>
<dd><p>Function to update some internal state after a process fork; this should be
called in the new process if the Python interpreter will continue to be used.
If a new executable is loaded into the new process, this function does not need
to be called.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyOS_CheckStack">
int <code class="descname">PyOS_CheckStack</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyOS_CheckStack" title="Permalink to this definition">¶</a></dt>
<dd><p>Return true when the interpreter runs out of stack space.  This is a reliable
check, but is only available when <code class="xref py py-const docutils literal"><span class="pre">USE_STACKCHECK</span></code> is defined (currently
on Windows using the Microsoft Visual C++ compiler).  <code class="xref py py-const docutils literal"><span class="pre">USE_STACKCHECK</span></code>
will be defined automatically; you should never change the definition in your
own code.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyOS_getsig">
PyOS_sighandler_t <code class="descname">PyOS_getsig</code><span class="sig-paren">(</span>int<em>&nbsp;i</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyOS_getsig" title="Permalink to this definition">¶</a></dt>
<dd><p>Return the current signal handler for signal <em>i</em>.  This is a thin wrapper around
either <code class="xref c c-func docutils literal"><span class="pre">sigaction()</span></code> or <code class="xref c c-func docutils literal"><span class="pre">signal()</span></code>.  Do not call those functions
directly! <code class="xref c c-type docutils literal"><span class="pre">PyOS_sighandler_t</span></code> is a typedef alias for <code class="xref c c-type docutils literal"><span class="pre">void</span>
<span class="pre">(*)(int)</span></code>.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyOS_setsig">
PyOS_sighandler_t <code class="descname">PyOS_setsig</code><span class="sig-paren">(</span>int<em>&nbsp;i</em>, PyOS_sighandler_t<em>&nbsp;h</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyOS_setsig" title="Permalink to this definition">¶</a></dt>
<dd><p>Set the signal handler for signal <em>i</em> to be <em>h</em>; return the old signal handler.
This is a thin wrapper around either <code class="xref c c-func docutils literal"><span class="pre">sigaction()</span></code> or <code class="xref c c-func docutils literal"><span class="pre">signal()</span></code>.  Do
not call those functions directly!  <code class="xref c c-type docutils literal"><span class="pre">PyOS_sighandler_t</span></code> is a typedef
alias for <code class="xref c c-type docutils literal"><span class="pre">void</span> <span class="pre">(*)(int)</span></code>.</p>
</dd></dl>

<dl class="function">
<dt id="c.Py_DecodeLocale">
wchar_t* <code class="descname">Py_DecodeLocale</code><span class="sig-paren">(</span>const char*<em>&nbsp;arg</em>, size_t<em>&nbsp;*size</em><span class="sig-paren">)</span><a class="headerlink" href="#c.Py_DecodeLocale" title="Permalink to this definition">¶</a></dt>
<dd><p>Decode a byte string from the locale encoding with the <a class="reference internal" href="../library/codecs.html#surrogateescape"><span class="std std-ref">surrogateescape
error handler</span></a>: undecodable bytes are decoded as
characters in range U+DC80..U+DCFF. If a byte sequence can be decoded as a
surrogate character, escape the bytes using the surrogateescape error
handler instead of decoding them.</p>
<p>Return a pointer to a newly allocated wide character string, use
<a class="reference internal" href="memory.html#c.PyMem_RawFree" title="PyMem_RawFree"><code class="xref c c-func docutils literal"><span class="pre">PyMem_RawFree()</span></code></a> to free the memory. If size is not <code class="docutils literal"><span class="pre">NULL</span></code>, write
the number of wide characters excluding the null character into <code class="docutils literal"><span class="pre">*size</span></code></p>
<p>Return <code class="docutils literal"><span class="pre">NULL</span></code> on decoding error or memory allocation error. If <em>size</em> is
not <code class="docutils literal"><span class="pre">NULL</span></code>, <code class="docutils literal"><span class="pre">*size</span></code> is set to <code class="docutils literal"><span class="pre">(size_t)-1</span></code> on memory error or set to
<code class="docutils literal"><span class="pre">(size_t)-2</span></code> on decoding error.</p>
<p>Decoding errors should never happen, unless there is a bug in the C
library.</p>
<p>Use the <a class="reference internal" href="#c.Py_EncodeLocale" title="Py_EncodeLocale"><code class="xref c c-func docutils literal"><span class="pre">Py_EncodeLocale()</span></code></a> function to encode the character string
back to a byte string.</p>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last">The <a class="reference internal" href="unicode.html#c.PyUnicode_DecodeFSDefaultAndSize" title="PyUnicode_DecodeFSDefaultAndSize"><code class="xref c c-func docutils literal"><span class="pre">PyUnicode_DecodeFSDefaultAndSize()</span></code></a> and
<a class="reference internal" href="unicode.html#c.PyUnicode_DecodeLocaleAndSize" title="PyUnicode_DecodeLocaleAndSize"><code class="xref c c-func docutils literal"><span class="pre">PyUnicode_DecodeLocaleAndSize()</span></code></a> functions.</p>
</div>
<div class="versionadded">
<p><span class="versionmodified">New in version 3.5.</span></p>
</div>
</dd></dl>

<dl class="function">
<dt id="c.Py_EncodeLocale">
char* <code class="descname">Py_EncodeLocale</code><span class="sig-paren">(</span>const wchar_t<em>&nbsp;*text</em>, size_t<em>&nbsp;*error_pos</em><span class="sig-paren">)</span><a class="headerlink" href="#c.Py_EncodeLocale" title="Permalink to this definition">¶</a></dt>
<dd><p>Encode a wide character string to the locale encoding with the
<a class="reference internal" href="../library/codecs.html#surrogateescape"><span class="std std-ref">surrogateescape error handler</span></a>: surrogate characters
in the range U+DC80..U+DCFF are converted to bytes 0x80..0xFF.</p>
<p>Return a pointer to a newly allocated byte string, use <a class="reference internal" href="memory.html#c.PyMem_Free" title="PyMem_Free"><code class="xref c c-func docutils literal"><span class="pre">PyMem_Free()</span></code></a>
to free the memory. Return <code class="docutils literal"><span class="pre">NULL</span></code> on encoding error or memory allocation
error</p>
<p>If error_pos is not <code class="docutils literal"><span class="pre">NULL</span></code>, <code class="docutils literal"><span class="pre">*error_pos</span></code> is set to the index of the
invalid character on encoding error, or set to <code class="docutils literal"><span class="pre">(size_t)-1</span></code> otherwise.</p>
<p>Use the <a class="reference internal" href="#c.Py_DecodeLocale" title="Py_DecodeLocale"><code class="xref c c-func docutils literal"><span class="pre">Py_DecodeLocale()</span></code></a> function to decode the bytes string back
to a wide character string.</p>
<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last">The <a class="reference internal" href="unicode.html#c.PyUnicode_EncodeFSDefault" title="PyUnicode_EncodeFSDefault"><code class="xref c c-func docutils literal"><span class="pre">PyUnicode_EncodeFSDefault()</span></code></a> and
<a class="reference internal" href="unicode.html#c.PyUnicode_EncodeLocale" title="PyUnicode_EncodeLocale"><code class="xref c c-func docutils literal"><span class="pre">PyUnicode_EncodeLocale()</span></code></a> functions.</p>
</div>
<div class="versionadded">
<p><span class="versionmodified">New in version 3.5.</span></p>
</div>
</dd></dl>

</div>
<div class="section" id="system-functions">
<span id="systemfunctions"></span><h1>System Functions<a class="headerlink" href="#system-functions" title="Permalink to this headline">¶</a></h1>
<p>These are utility functions that make functionality from the <a class="reference internal" href="../library/sys.html#module-sys" title="sys: Access system-specific parameters and functions."><code class="xref py py-mod docutils literal"><span class="pre">sys</span></code></a> module
accessible to C code.  They all work with the current interpreter thread’s
<a class="reference internal" href="../library/sys.html#module-sys" title="sys: Access system-specific parameters and functions."><code class="xref py py-mod docutils literal"><span class="pre">sys</span></code></a> module’s dict, which is contained in the internal thread state structure.</p>
<dl class="function">
<dt id="c.PySys_GetObject">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a> *<code class="descname">PySys_GetObject</code><span class="sig-paren">(</span>const char<em>&nbsp;*name</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySys_GetObject" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: Borrowed reference.</em><p>Return the object <em>name</em> from the <a class="reference internal" href="../library/sys.html#module-sys" title="sys: Access system-specific parameters and functions."><code class="xref py py-mod docutils literal"><span class="pre">sys</span></code></a> module or <em>NULL</em> if it does
not exist, without setting an exception.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySys_SetObject">
int <code class="descname">PySys_SetObject</code><span class="sig-paren">(</span>const char<em>&nbsp;*name</em>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*v</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySys_SetObject" title="Permalink to this definition">¶</a></dt>
<dd><p>Set <em>name</em> in the <a class="reference internal" href="../library/sys.html#module-sys" title="sys: Access system-specific parameters and functions."><code class="xref py py-mod docutils literal"><span class="pre">sys</span></code></a> module to <em>v</em> unless <em>v</em> is <em>NULL</em>, in which
case <em>name</em> is deleted from the sys module. Returns <code class="docutils literal"><span class="pre">0</span></code> on success, <code class="docutils literal"><span class="pre">-1</span></code>
on error.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySys_ResetWarnOptions">
void <code class="descname">PySys_ResetWarnOptions</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#c.PySys_ResetWarnOptions" title="Permalink to this definition">¶</a></dt>
<dd><p>Reset <a class="reference internal" href="../library/sys.html#sys.warnoptions" title="sys.warnoptions"><code class="xref py py-data docutils literal"><span class="pre">sys.warnoptions</span></code></a> to an empty list.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySys_AddWarnOption">
void <code class="descname">PySys_AddWarnOption</code><span class="sig-paren">(</span>wchar_t<em>&nbsp;*s</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySys_AddWarnOption" title="Permalink to this definition">¶</a></dt>
<dd><p>Append <em>s</em> to <a class="reference internal" href="../library/sys.html#sys.warnoptions" title="sys.warnoptions"><code class="xref py py-data docutils literal"><span class="pre">sys.warnoptions</span></code></a>.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySys_AddWarnOptionUnicode">
void <code class="descname">PySys_AddWarnOptionUnicode</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*unicode</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySys_AddWarnOptionUnicode" title="Permalink to this definition">¶</a></dt>
<dd><p>Append <em>unicode</em> to <a class="reference internal" href="../library/sys.html#sys.warnoptions" title="sys.warnoptions"><code class="xref py py-data docutils literal"><span class="pre">sys.warnoptions</span></code></a>.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySys_SetPath">
void <code class="descname">PySys_SetPath</code><span class="sig-paren">(</span>wchar_t<em>&nbsp;*path</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySys_SetPath" title="Permalink to this definition">¶</a></dt>
<dd><p>Set <a class="reference internal" href="../library/sys.html#sys.path" title="sys.path"><code class="xref py py-data docutils literal"><span class="pre">sys.path</span></code></a> to a list object of paths found in <em>path</em> which should
be a list of paths separated with the platform’s search path delimiter
(<code class="docutils literal"><span class="pre">:</span></code> on Unix, <code class="docutils literal"><span class="pre">;</span></code> on Windows).</p>
</dd></dl>

<dl class="function">
<dt id="c.PySys_WriteStdout">
void <code class="descname">PySys_WriteStdout</code><span class="sig-paren">(</span>const char<em>&nbsp;*format</em>, ...<span class="sig-paren">)</span><a class="headerlink" href="#c.PySys_WriteStdout" title="Permalink to this definition">¶</a></dt>
<dd><p>Write the output string described by <em>format</em> to <a class="reference internal" href="../library/sys.html#sys.stdout" title="sys.stdout"><code class="xref py py-data docutils literal"><span class="pre">sys.stdout</span></code></a>.  No
exceptions are raised, even if truncation occurs (see below).</p>
<p><em>format</em> should limit the total size of the formatted output string to
1000 bytes or less – after 1000 bytes, the output string is truncated.
In particular, this means that no unrestricted “%s” formats should occur;
these should be limited using “%.&lt;N&gt;s” where &lt;N&gt; is a decimal number
calculated so that &lt;N&gt; plus the maximum size of other formatted text does not
exceed 1000 bytes.  Also watch out for “%f”, which can print hundreds of
digits for very large numbers.</p>
<p>If a problem occurs, or <a class="reference internal" href="../library/sys.html#sys.stdout" title="sys.stdout"><code class="xref py py-data docutils literal"><span class="pre">sys.stdout</span></code></a> is unset, the formatted message
is written to the real (C level) <em>stdout</em>.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySys_WriteStderr">
void <code class="descname">PySys_WriteStderr</code><span class="sig-paren">(</span>const char<em>&nbsp;*format</em>, ...<span class="sig-paren">)</span><a class="headerlink" href="#c.PySys_WriteStderr" title="Permalink to this definition">¶</a></dt>
<dd><p>As <a class="reference internal" href="#c.PySys_WriteStdout" title="PySys_WriteStdout"><code class="xref c c-func docutils literal"><span class="pre">PySys_WriteStdout()</span></code></a>, but write to <a class="reference internal" href="../library/sys.html#sys.stderr" title="sys.stderr"><code class="xref py py-data docutils literal"><span class="pre">sys.stderr</span></code></a> or <em>stderr</em>
instead.</p>
</dd></dl>

<dl class="function">
<dt id="c.PySys_FormatStdout">
void <code class="descname">PySys_FormatStdout</code><span class="sig-paren">(</span>const char<em>&nbsp;*format</em>, ...<span class="sig-paren">)</span><a class="headerlink" href="#c.PySys_FormatStdout" title="Permalink to this definition">¶</a></dt>
<dd><p>Function similar to PySys_WriteStdout() but format the message using
<a class="reference internal" href="unicode.html#c.PyUnicode_FromFormatV" title="PyUnicode_FromFormatV"><code class="xref c c-func docutils literal"><span class="pre">PyUnicode_FromFormatV()</span></code></a> and don’t truncate the message to an
arbitrary length.</p>
<div class="versionadded">
<p><span class="versionmodified">New in version 3.2.</span></p>
</div>
</dd></dl>

<dl class="function">
<dt id="c.PySys_FormatStderr">
void <code class="descname">PySys_FormatStderr</code><span class="sig-paren">(</span>const char<em>&nbsp;*format</em>, ...<span class="sig-paren">)</span><a class="headerlink" href="#c.PySys_FormatStderr" title="Permalink to this definition">¶</a></dt>
<dd><p>As <a class="reference internal" href="#c.PySys_FormatStdout" title="PySys_FormatStdout"><code class="xref c c-func docutils literal"><span class="pre">PySys_FormatStdout()</span></code></a>, but write to <a class="reference internal" href="../library/sys.html#sys.stderr" title="sys.stderr"><code class="xref py py-data docutils literal"><span class="pre">sys.stderr</span></code></a> or <em>stderr</em>
instead.</p>
<div class="versionadded">
<p><span class="versionmodified">New in version 3.2.</span></p>
</div>
</dd></dl>

<dl class="function">
<dt id="c.PySys_AddXOption">
void <code class="descname">PySys_AddXOption</code><span class="sig-paren">(</span>const wchar_t<em>&nbsp;*s</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PySys_AddXOption" title="Permalink to this definition">¶</a></dt>
<dd><p>Parse <em>s</em> as a set of <a class="reference internal" href="../using/cmdline.html#id5"><code class="xref std std-option docutils literal"><span class="pre">-X</span></code></a> options and add them to the current
options mapping as returned by <a class="reference internal" href="#c.PySys_GetXOptions" title="PySys_GetXOptions"><code class="xref c c-func docutils literal"><span class="pre">PySys_GetXOptions()</span></code></a>.</p>
<div class="versionadded">
<p><span class="versionmodified">New in version 3.2.</span></p>
</div>
</dd></dl>

<dl class="function">
<dt id="c.PySys_GetXOptions">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a> *<code class="descname">PySys_GetXOptions</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#c.PySys_GetXOptions" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: Borrowed reference.</em><p>Return the current dictionary of <a class="reference internal" href="../using/cmdline.html#id5"><code class="xref std std-option docutils literal"><span class="pre">-X</span></code></a> options, similarly to
<a class="reference internal" href="../library/sys.html#sys._xoptions" title="sys._xoptions"><code class="xref py py-data docutils literal"><span class="pre">sys._xoptions</span></code></a>.  On error, <em>NULL</em> is returned and an exception is
set.</p>
<div class="versionadded">
<p><span class="versionmodified">New in version 3.2.</span></p>
</div>
</dd></dl>

</div>
<div class="section" id="process-control">
<span id="processcontrol"></span><h1>Process Control<a class="headerlink" href="#process-control" title="Permalink to this headline">¶</a></h1>
<dl class="function">
<dt id="c.Py_FatalError">
void <code class="descname">Py_FatalError</code><span class="sig-paren">(</span>const char<em>&nbsp;*message</em><span class="sig-paren">)</span><a class="headerlink" href="#c.Py_FatalError" title="Permalink to this definition">¶</a></dt>
<dd><p id="index-0">Print a fatal error message and kill the process.  No cleanup is performed.
This function should only be invoked when a condition is detected that would
make it dangerous to continue using the Python interpreter; e.g., when the
object administration appears to be corrupted.  On Unix, the standard C library
function <code class="xref c c-func docutils literal"><span class="pre">abort()</span></code> is called which will attempt to produce a <code class="file docutils literal"><span class="pre">core</span></code>
file.</p>
</dd></dl>

<dl class="function">
<dt id="c.Py_Exit">
void <code class="descname">Py_Exit</code><span class="sig-paren">(</span>int<em>&nbsp;status</em><span class="sig-paren">)</span><a class="headerlink" href="#c.Py_Exit" title="Permalink to this definition">¶</a></dt>
<dd><p id="index-1">Exit the current process.  This calls <a class="reference internal" href="init.html#c.Py_FinalizeEx" title="Py_FinalizeEx"><code class="xref c c-func docutils literal"><span class="pre">Py_FinalizeEx()</span></code></a> and then calls the
standard C library function <code class="docutils literal"><span class="pre">exit(status)</span></code>.  If <a class="reference internal" href="init.html#c.Py_FinalizeEx" title="Py_FinalizeEx"><code class="xref c c-func docutils literal"><span class="pre">Py_FinalizeEx()</span></code></a>
indicates an error, the exit status is set to 120.</p>
<div class="versionchanged">
<p><span class="versionmodified">Changed in version 3.6: </span>Errors from finalization no longer ignored.</p>
</div>
</dd></dl>

<dl class="function">
<dt id="c.Py_AtExit">
int <code class="descname">Py_AtExit</code><span class="sig-paren">(</span>void (<em>*func</em>)()<span class="sig-paren">)</span><a class="headerlink" href="#c.Py_AtExit" title="Permalink to this definition">¶</a></dt>
<dd><p id="index-2">Register a cleanup function to be called by <a class="reference internal" href="init.html#c.Py_FinalizeEx" title="Py_FinalizeEx"><code class="xref c c-func docutils literal"><span class="pre">Py_FinalizeEx()</span></code></a>.  The cleanup
function will be called with no arguments and should return no value.  At most
32 cleanup functions can be registered.  When the registration is successful,
<a class="reference internal" href="#c.Py_AtExit" title="Py_AtExit"><code class="xref c c-func docutils literal"><span class="pre">Py_AtExit()</span></code></a> returns <code class="docutils literal"><span class="pre">0</span></code>; on failure, it returns <code class="docutils literal"><span class="pre">-1</span></code>.  The cleanup
function registered last is called first. Each cleanup function will be called
at most once.  Since Python’s internal finalization will have completed before
the cleanup function, no Python APIs should be called by <em>func</em>.</p>
</dd></dl>

</div>


          </div>
        </div>
      </div>
      <div class="sphinxsidebar" role="navigation" aria-label="main navigation">
        <div class="sphinxsidebarwrapper">
  <h3><a href="../contents.html">Table Of Contents</a></h3>
  <ul>
<li><a class="reference internal" href="#">Operating System Utilities</a></li>
<li><a class="reference internal" href="#system-functions">System Functions</a></li>
<li><a class="reference internal" href="#process-control">Process Control</a></li>
</ul>

  <h4>Previous topic</h4>
  <p class="topless"><a href="utilities.html"
                        title="previous chapter">Utilities</a></p>
  <h4>Next topic</h4>
  <p class="topless"><a href="import.html"
                        title="next chapter">Importing Modules</a></p>
  <div role="note" aria-label="source link">
    <h3>This Page</h3>
    <ul class="this-page-menu">
      <li><a href="../bugs.html">Report a Bug</a></li>
      <li>
        <a href="https://github.com/python/cpython/blob/3.6/Doc/c-api/sys.rst"
            rel="nofollow">Show Source
        </a>
      </li>
    </ul>
  </div>
        </div>
      </div>
      <div class="clearer"></div>
    </div>  
    <div class="related" role="navigation" aria-label="related navigation">
      <h3>Navigation</h3>
      <ul>
        <li class="right" style="margin-right: 10px">
          <a href="../genindex.html" title="General Index"
             >index</a></li>
        <li class="right" >
          <a href="../py-modindex.html" title="Python Module Index"
             >modules</a> |</li>
        <li class="right" >
          <a href="import.html" title="Importing Modules"
             >next</a> |</li>
        <li class="right" >
          <a href="utilities.html" title="Utilities"
             >previous</a> |</li>
        <li><img src="../_static/py.png" alt=""
                 style="vertical-align: middle; margin-top: -1px"/></li>
        <li><a href="https://www.python.org/">Python</a> &#187;</li>
        <li>
          <span class="language_switcher_placeholder">en</span>
          <span class="version_switcher_placeholder">3.6.3</span>
          <a href="../index.html">Documentation </a> &#187;
        </li>

          <li class="nav-item nav-item-1"><a href="index.html" >Python/C API Reference Manual</a> &#187;</li>
          <li class="nav-item nav-item-2"><a href="utilities.html" >Utilities</a> &#187;</li>
    <li class="right">
        

    <div class="inline-search" style="display: none" role="search">
        <form class="inline-search" action="../search.html" method="get">
          <input placeholder="Quick search" type="text" name="q" />
          <input type="submit" value="Go" />
          <input type="hidden" name="check_keywords" value="yes" />
          <input type="hidden" name="area" value="default" />
        </form>
    </div>
    <script type="text/javascript">$('.inline-search').show(0);</script>
         |
    </li>

      </ul>
    </div>  
    <div class="footer">
    &copy; <a href="../copyright.html">Copyright</a> 2001-2017, Python Software Foundation.
    <br />
    The Python Software Foundation is a non-profit corporation.
    <a href="https://www.python.org/psf/donations/">Please donate.</a>
    <br />
    Last updated on Oct 14, 2017.
    <a href="../bugs.html">Found a bug</a>?
    <br />
    Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.6.4.
    </div>

  </body>
</html>